This invention relates to communications systems, and more specifically, to a method and system for authorizing wireless users to roam in selected radio coverage areas.
Over the last twenty years wireless communications systems have evolved from their simple origins of single-operator wireless networks to multi-operator seamless roaming networks that allow wireless callers to receive and to initiate calls from wherever they might bexe2x80x94in their home service territory or in a roaming area that might even be located in a foreign country. A great number of technical and administrative obstacles had to be overcome before a subscriber of one wireless service provider could transparently receive wireless communications services from the network of another service provider. For example, multilateral operating agreements had to be negotiated between service providers to standardize communications between the dissimilar switching systems of the different service providers"" networks. Most importantly, a common signaling protocol and signaling messages format and definition had to be agreed upon by all participating wireless service providers for exchange of call handling messages between their switching systems.
Because of the significant differences in the communications systems architectures and switching systems used by the different service providers, only a small number of common signaling messages for essential call processing functions (e.g., registration) could be agreed upon by the different service providers. As a result, a service provider-specific implementation for addressing a particular problem, such as wireless fraud, could not be universally adopted by all service providers. For example, the common practice that requires a wireless subscriber to provide authentication information before receiving service, could not be implemented for all roaming callers. The inability to implement an authentication procedure for some roaming callers may be attributed to a variety of factors not the least of which is the home carriers"" unwillingness to implement authentication procedures in their networks.
Taking advantage of the lack of communications between switches for fraud prevention information, roaming areas have been targeted as launching pads to initiate fraudulent calls, thereby depriving wireless communications carriers of yearly revenues estimated at over half a billion dollars. Typical fraudulent ploys for the theft of wireless communications services include, for example, eavesdroppers intercepting legitimate subscriber""s wireless telephone sets"" Mobile Identification Numbers (MIN) and Electronic Serial Numbers (ESN) pairs from wireless communications frequencies, and publicizing those pairs over fraud-information-dissemination forums, such as electronic bulletin boards. The intercepted MINs and ESNs pairs are then programmed into an illegal wireless device to enable a fraud perpetrator to initiate roaming wireless calls that are charged to the legitimate subscribers"" accounts.
In response to this ever-growing problem, some communications carriers have felt compelled to implement additional fraud prevention measures that either deny or restrict access to their network for certain types of wireless calls. For example, some communications carriers have implemented drastic fraud prevention procedures, such as denial of service for calls originated from particular roaming areas.
While these procedures have been quite effective in limiting incidences of wireless communications fraud, it is undeniable that they present certain shortcomings. For example, denying access to a wireless network for calls originated from certain roaming areas may have the negative effect of possibly denying access to communications services to a great number of legitimate wireless subscribers when those services might be most needed. The denial of service is particularly vexing to a subscriber when no land-line communications services are available, as on a deserted road. Equally significant is the loss of roaming and air time charges and (possibly) long distance revenues that the service provider would have received as proceeds for the completion of the denied calls. Hence, it is a continuing problem for wireless communications carriers to implement fraud prevention measures that are neither unduly inconvenient to wireless subscribers nor overly revenue-limiting for wireless service providers.
The present invention is directed to a wireless network that grants roaming privileges to a wireless communications service subscriber for one or more selected roaming areas only during a limited time period that is identified in a profile of that subscriber. In an illustrative embodiment of the principles of the invention, a wireless communications service subscriber is allowed to set a profile that identifies a chosen time window within which wireless calls originated from one or more selected roaming areas are permitted to be completed while wireless calls that are initiated outside of the chosen time window and that are originated from any one of these selected roaming areas are automatically terminated. Similarly, calls initiated from unauthorized roaming areas are also terminated.
The subscriber""s profile may be, for example, a data structure, such as a table, that associates the subscriber""s mobile end-user device MIN and/or ESN to the time window for the selected roaming area(s). Hence, when the subscriber powers on a mobile end-user device to register from a selected roaming area, the MIN and/or ESN associated with the mobile end-user device is used as a search key to retrieve the subscriber""s profile. The subscriber""s profile may be stored, for example, at the Home Location Register of the subscriber""s service provider. The current date, i.e., the date at which the registration process is initiated, is then compared to the time window information retrieved from the profile. If the current date falls within the range of permissible dates specified in the profile for the selected roaming area, the registration process proceeds in a conventional manner. Otherwise, a registration denial procedure may be initiated based, for example, on the subscriber""s roaming history.
According to an aspect of the invention, if the MIN/ESN pair associated with the mobile end-user device indicates, for example, that the subscriber is a frequent roamer, a call intercept feature may be activated for the mobile end-user device. Hence, when a call is initiated from the mobile end-user device, the call is automatically routed to a live or automatic operator instead of its intended destination. The operator then prompts the caller for certain information to validate the caller""s identity. If the information provided by the caller is valid, the call is then completed to its intended destination. Otherwise, the call is terminated.
According to another aspect of the invention, when fraud is detected for a given subscriber within a given roaming area, the serving wireless service provider can deny services to that particular subscriber either for a finite amount of time or on a permanent basis. Alternatively, services may be allowed or denied based on the results of further verification of the subscriber""s identity.